package com.myrule;
import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.AbstractLoadBalancerRule;
import com.netflix.loadbalancer.ILoadBalancer;
import com.netflix.loadbalancer.Server;

import java.util.List;
import java.util.concurrent.ThreadLocalRandom;

public class MyRandomRule extends AbstractLoadBalancerRule {

    //自定义负载均衡规则
    //每个服务访问5次，换下一个服务。
    private int total=0;    //被访问的次数
    private int currentIndex=0; //当前是谁在提供服务

    //@edu.umd.cs.findbugs.annotations.SuppressWarnings(value = "RCN_REDUNDANT_NULLCHECK_OF_NULL_VALUE")
    public Server choose(ILoadBalancer lb, Object key) {
        if (lb == null) {
            return null;
        }
        Server server = null;

        while (server == null) {
            if (Thread.interrupted()) {
                return null;
            }
            List<Server> upList = lb.getReachableServers(); //获取活着的服务
            List<Server> allList = lb.getAllServers();  //获取全部的服务

            int serverCount = allList.size();
            if (serverCount == 0) {

                return null;
            }

//            int index = chooseRandomInt(serverCount);   //生成区间随机数
//            server = upList.get(index);     //从活着的服务中随机获得一个服务
            //自定义规则=======================================================
            if (total < 5) {
                server=upList.get(currentIndex);
                total++;
            }else {
                total=0;
                currentIndex++;
                if (currentIndex >= upList.size()) {
                    currentIndex=0;
                }
                upList.get(currentIndex);
            }
            //=================================================================
            if (server == null) {

                Thread.yield();
                continue;
            }

            if (server.isAlive()) {
                return (server);
            }


            server = null;
            Thread.yield();
        }

        return server;

    }

    protected int chooseRandomInt(int serverCount) {
        return ThreadLocalRandom.current().nextInt(serverCount);
    }

    @Override
    public Server choose(Object key) {
        return choose(getLoadBalancer(), key);
    }

    @Override
    public void initWithNiwsConfig(IClientConfig clientConfig) {
        // TODO Auto-generated method stub
    }
}
